Prepare the slow cooker: Place chicken breasts in the bottom of a 6-quart slow cooker. Sprinkle the ranch seasoning mix evenly over the chicken, then pour in the chicken broth.
Cook the chicken: Cover and cook on low for 6-8 hours or high for 3-4 hours, until the chicken is tender and easily shreddable.
Shred the chicken: Remove the chicken from the slow cooker and shred it using two forks. Return the shredded chicken to the slow cooker, mixing it with the cooking liquid.
Add creamy elements: Stir in the sour cream and cream cheese (if using) until fully combined. Add the crumbled turkey bacon and half of the shredded cheddar cheese, stirring to incorporate.
Toast the buns: Brush the sandwich buns with olive oil and toast them on a skillet over medium heat for 1-2 minutes per side until golden brown.
Assemble the sandwiches: Spoon the chicken mixture onto the bottom half of each bun. Sprinkle with remaining cheddar cheese and add optional toppings like lettuce or tomatoes. Place the top bun and serve warm!